1. Field of the Invention
The present invention is directed to a propulsion device for propelling an object. More particularly, the present invention is directed to a propulsion device manufactured using off-the-shelf parts for propelling biodegradable objects.
2. Discussion of the Background
A propulsion device generally includes a fuel chamber connected to a barrel having a longitudinal bore and an ignition system for igniting fuel contained in the fuel chamber. These devices may propel objects with live ammunition or alternatively objects without ammunition. In addition, there exist toy cannons and firework propulsion devices used for entertainment purposes, as well as other propelling devices used for simulating an actual cannon.
For example, FIGS. 6-8 of U.S. Pat. No. 4,369,592 disclose a conventional propulsion device used to propel a ball or compressible object. The propulsion device includes a loading chamber, a firing chamber, and a loading mechanism. To operate this device, a firecracker is first placed and ignited in the loading chamber. Then, the loading mechanism is laterally slid backwards and the ignited firecracker drops into the firing chamber, explodes and propels the compressible object.
A problem with this conventional propulsion device is that it is difficult and very dangerous to load. That is, the firecracker must first be lit and then the loading mechanism must manually be retracted. Thus, there is a great likelihood that the firecracker will prematurely explode and injure the operator of the device. Another problem with this device is that firecrackers are illegal in most states. Therefore, the legal use of this device is greatly restricted.
A simpler propulsion device, which uses lighter fluid as an explosive material, is shown in FIG. 8 of U.S. Pat. No. 3,745,691. This device includes a hollow tube having two rigid disks disposed at one end of the tube. Each of the disks has a small central opening. To operate this device, lighter fluid is squirted into a space between the disks through one of the central openings. The tube is then shaken several times to distribute the lighter fluid and to allow at least part of it to vaporize. The device may then be ignited using a lighted match.
Although this device is simpler to manufacture and operate than that previously discussed, the same problem exists in that the device is very dangerous to use. That is, the lighter fluid may burst into flames and injure the person igniting the device.
Another problem with conventional propulsion devices is that the propelled object is usually a rubber ball or a metal object. After ejection of the object, it must be retrieved to prevent unwanted littering. Also, conventional devices are generally limited to firing objects having a predetermined diameter which precisely fit into the bore of the firing barrel. This greatly limits the types of objects that may be propelled. Additionally, a ball or metal object that may be fired does not provide a tight seal and a proper lubrication to the inside of the bore for optimum firing range and consistency.
A general problem with conventional propulsion devices is in the type of fuel used. Many devices use either a liquid fuel (e.g., lighter fluid), firecrackers, or solid carbide pellets dissolved in water to create a combustible mixture. One problem with using a liquid fuel is it must first be partially vaporized. Therefore, the propulsion device must be shaken to vaporize part of the liquid fuel, which adds an additional step in the firing process. The problem with using carbide pellets dissolved in water is that during the explosion, the excess water may be sprayed throughout the device. Thus, the device must be cleaned on a regular basis. Further, the above fuels do not create a uniform combustible mixture, and thus a uniform and highly reliable detonation is difficult to obtain.
Yet another problem with conventional propulsion devices is that the fueling process is inconvenient and cumbersome. For example, many devices require fuel to be first injected into the fuel chamber, and then the fuel chamber is sealed. Thus, the fueling process requires an excessive number of steps in order to create a combustible mixture.
Consequently, there is a need for a novel propulsion device which is simple and inexpensive to manufacture by using off-the-shelf parts, one which is easy to fuel, and one which is safe to operate. There is also a need for a propulsion device which uses a gaseous fuel that is consistent and uniform in mixture and which is easily dispensed into the device. It is also desirable to have a propulsion device that is capable of and suitable for propelling biodegradable products, which after propelling would not need to be retrieved. Further, a propulsion device with a beveled end capable of cutting into and propelling parts of objects having an irregular shape is needed. Additionally, there is a need for a device with interchangeable bores some fitted with noise reducing holes that allow the gas to expand slightly before exiting the bore producing a firing with reduced noise.